In recent years, advancements in the design and surgical biopsy needles and their use have enabled practitioners to extract substantial volumes of tissue using surgical biopsy needles as opposed to more invasive surgical procedures.
One representative biopsy needle system is the MAMATOME.RTM. Breast Biopsy System of Biopsis Medical, Inc., Irvine, Calif. The MAMATOME.RTM. Breast Biopsy System uses a dual-lumen biopsy needle 10 shown in cross-section in FIG. 1. The biopsy needle 10 has a sidewall 12 and an inner wall 14. The inner wall 14 divides the interior of the biopsy needle into a main lumen 16 and a vacuum lumen 18. The distal end 20 of the dual-lumen biopsy needle is pointed to facilitate ease of insertion into the tissue of a patient. Proximate the distal end 20 of the dual-lumen biopsy needle an aperture 16 extends through the sidewall 12 and communicates with the main lumen 16. The inner wall 14 has a plurality of holes 24 corresponding to the aperture 22.
In use, under stereotactic or ultrasonic guidance, the needle is positioned within the affected tissue 25 to align the aperture 22 with the suspect lesion. A vacuum is then applied to the vacuum lumen 18 to aspirate tissue into the aperture 22. Thereafter a rotating cutter 26 is axially advanced within the main lumen 16 cutting and capturing a specimen in the cavity 28. The vacuum is then stopped, the rotating cutter 26 is axially withdrawn from the main lumen 16 and thereafter the tissue specimen can be removed from the cavity 28. A void 30 remains in affected tissue. The dual-lumen biopsy needle 10 can be axially rotated about axis A so that more tissue can be drawn into the aperture 22, severed and removed using the rotating cutter as discussed above. If the doctor should elect to rotate the biopsy needle about axis A 360 degrees so as to remove a maximum amount of tissue, a considerable void can be left in the affected tissue of the patient.
Typically, the biopsy is being performed to determine whether the lesion is cancerous. If so, subsequent surgery may be required to remove further tissue from around the now created void. In order to mark the site of the biopsy, the prior art has developed a number of marking apparatus. One representative marking apparatus is the MICROMARK.TM. II Tissue Marker of Biopsis Medical, Inc. This device has a flexible introducer with a radiographic tissue marker or clip at its distal end. The flexible introducer is axially inserted in the main lumen 16 of the biopsy needle. When the distal end of the flexible introducer reaches the aperture 16, it is biased to extend out of the aperture. Thereafter, a release button on a deployment actuator is pushed which causes axial advancement and disengagement of the clip, which is substantially configured as a staple, into the wall of the void 30. Thereafter, the flexible introducer and the biopsy needle can be removed from the affected tissue with the marker indicating the approximate biopsy site.
One problem with the MICROMARK.TM. II Tissue Marker is that it requires a complicated deployment structure that is subject to failure. It is a reoccurring problem that the clip does not actually disengage when the deployment catheter is pushed. A more pronounced problem with this type of marking system is evident when the biopsy is conducted on breast tissue. Referring to FIGS. 2A and 2B, typically when a mammogram is performed, the breast 32 is compressed between a pair of plates 34, 36 and the biopsy is performed with the breast in compression. When the clip, 32 is inserted using the MICROMARK.TM. II Tissue Marker or similar devices, the position of the clip is satisfactory with the breast in compression. However, since the clip is embedded into the tissue adjacent to the cavity, when compression is removed and the breast is returned to its natural state, the clip will migrate relative to the biopsy void 30 as illustrated in FIGS. 3A and 3B. This has the unfortunate result of not leaving the clip in the precise location of the biopsy void. Thus, if analysis of the removed tissue indicates a need for further surgery to remove more tissue around the site of the biopsy, the surgeon may be directed to the wrong site when the clip is later located using imaging techniques. This can result in the surgeon having to remove more tissue than may have been required had the site of the biopsy void been accurately marked, possibly resulting in undue physical deformity and increased surgical morbidity. In a worst case, the surgeon may even miss removing cancerous tissue because of the mis-marking of the site of the biopsy, leaving the patient subject to the risk of a malignant tumor.
In addition to the MICROMARK.TM. II Tissue Marker described above, there are other prior art systems intended to mark the site of a biopsy. These systems are designed for surgical removal shortly after deployment. They have in common a wire or cable extensions to the skin or surface of an organ. For example, Heaton, U.S. Pat. No. 5,879,357, teaches a marker having slats including a living hinge. The slats are laterally expandible to mark a suspect lesion. However, the doctor must actuate the slats into their expanded position which complicates the process of marking the biopsy void. In addition, Heaton requires a cable which is "sufficiently rigid" to assist in maintaining the marker in a deployed position. This cable remains attached to the implanted marker. This structure has the obvious disadvantage that the cable provides a vehicle for infection. Moreover, in the event the analysis of the tissue is negative, presumably the marker and the cable would have to be removed from the breast, therefore subjecting the patient to further unnecessary trauma.
Simon, U.S. Pat. No. 4,790,329, teaches a springing barb as part of a needle intended to be implanted under radiological examination in a patient to mark the cite of a lesion. According to Simon, this springing barb, as well as a cannula for implanting the barb, is intended to be left in place in the breast for locating the site of a lesion for a future biopsy. Thus, the structure of Simon is not suitable for marking the site where a biopsy has been taken because, as with Heaton, if in fact no further removal of tissue is necessary because the analysis of lesion comes back negative, the structure of Simon would have to be removed somehow.
Kvavle, U.S. Pat. No. 4,007,732, teaches radiographic resilient barbs that may be compressed and loaded into an implanting device. The barbs expand upon being advanced through the inserting device. Kvavle does not teach an apparatus for marking the site of a already conducted biopsy, but rather a system for marking the site of a lesion for a future biopsy. Kvavle teaches a wire 4 connected to the barbs which extend through the skin to provide an apparatus for locating the site of future biopsy. Again, the structure of Kvavle has the same shortcomings of Simon and Heaton, namely it is not suitable for marking the site where a biopsy has already been conducted because it leaves a wire extending through the skin of the patient.
The present invention is directed toward overcoming one or more of the problems discussed above.